Friday, August 21, 2009

Audio Cables and Power

So why are cables so important? Try disconnecting them and see if you still get music. Okay that's a stupid answer, but it still makes sense when you think about it. The power coming from the wall is in the form of AC Alternating Current. It's noisy, grimy nastiness. You don't want to make an audio signal out of that. So let's assume we have perfect power coming to our CD player. Our CD player uses a rectifier to create a DC signal which is in turn inverted back into an AC signal to be sent down the cables.

In a perfect world all of your components would be soldered together. However, that isn't the case, they have a distance to travel. So we have our perfect AC signal traveling from our CD player to our preamplifier/receiver. What happens to it while it's traveling down the cable? Lots of things. There are a few terms: Inductance, Capacitance, and Resistance. All are important in their own right. Resistance is the... you got it... resistance to the flow of electricity. If our goal is to have all of our connectors soldered, then effectively we want zero resistance so that the current flows quickly and accurate. With Capacitance, that's how a cable filters the signal and stores energy. There are a few theories with capacitance. High capacitance often means that high frequencies are rolled off, but it also means less noise. Low capacitance means that you have a more detailed cable because frequencies aren't rolled off. Well why would you want either? If you have the proper design, you will be able to have low capacitance AND low noise. Inductance is when a cable charges and releases energy, which reflects back into the cable. It's why shielding is a double-edged sword. Shielding blocks EMI/RFI, but it also raises inductance.

So there are a few paths for cable design. NEVER buy a networked cable. I know Karen Sumner of Transparent, brilliant woman, she can sell snake oil to a snake. Networks are just .1 filter capacitors in a shiny resin box.

Her cables are stranded cables. Stranded cables inherently cause inter-modulation (most cheapo cables like blue-jeans, monoprice, etc., are stranded). Intermodulation is when a signal jumps from strand to strand. With stranded conductors, each strand has a different resistance. So when a signal is sent down that conductor, it is copied onto all the different strands. However, that same signal shows up at different times at the next component. This means some of the signal is out of phase, and some pieces of the signal are telling the speaker driver to move out, when at the same time other pieces are telling it to move in. Obviously loss of clarity.

Another design theory uses solid-core. This means one signal at one time and no intermodulation. Sounds perfect, right? Nope. There is a new problem that's face with Solid Core conductors. As the gauge size gets larger than 14awg, we get what's called the Skin effect. This is the tendency for high frequencies to travel towards the outside of a conductor. On the outside of the conductor they travel at faster rates. This also causes timing and phase errors. However, the larger gauge size also means more current. Current is speed, and it also allows a wider range of frequency extension.

Now there are a few other theories. Multiple small gauge, solid core conductors. If the gauge is small enough then the skin effect doesnt occur. With a solid core conductor that is isolated from others, then you also dont have intermodular distortion. Morrow Audio uses small solid core conductors without shielding.

Another idea is a flat solid core conductor. Both Goertz and Tara labs use this theory, and they are some of the best cables I've had the chance to listen to. The flat conductor is by far the most frequency-linear. This means that it doesn't emphasize any frequency, it's neutral and clear. Tara Labs cables have some of the best low-frequency extension and control of any cable i've heard.

There are even more options than this. The type of dielectric, copper/silver/gold cables, silver coated copper, etc.

Now what's my recommendation? I'd go with Goertz, Tara Labs, or Morrow Audio. All three companies make some excellent cables. I would buy cables before an isolation transformer. I am selling a custom-made Tara Labs cable right now. It was made custom using their RSC conductors and is the same performance level as their The ONE speaker cable. I'm selling it on audiogon for $1175, it's an excellently musical and detailed cable. It's called Tara Labs The EKC. Retailed for $3600 when it was being made last year. Ended up costing too much to make it so Brian Kurtz and Matt Sellers stopped making them.

Goertz is cheaper, but also excellent. I often return to my Goertz Boa MI3 cables for nostalgia purposes. I don't recommend Goertz interconnects. I'd go with Morrow interconnects or Tara Labs.

So let's take a step back to our signal path. Why do cables make a difference? Because of everything I said above. The more expensive cables use better dielectrics, higher quality conductors, and have more R&D behind them. Tara Labs uses Rectangular Solid Core conductors that are 8N pure... which means 8 nines.... 99.99999999% pure. Cheap conductors are maybe 99.9% pure. They are also soft-anealed. This means that they are one long grain. So the signal isn't jumping from grain to grain within the conductor. Jumping causes distortion. Those jumps cause vibration, and vibration is the enemy. So with a nice conductor you will have no noise, with a bad conductor you will have oodles of noise.

What does that translate to? Less noise means more spacial cues, deeper and wider soundstage by a large margin, more transparency, more frequency extension, clarity, musicality, and proper rhythm and timing. All those are sacrificed with a bad cable. Going from a cheap cable to a nice cable will be the biggest upgrade you've ever made to your system. Just try and stay away from snake oil.

OKAY onto the next question...
2. 220/240 is standard I believe. You can call and ask. I've never used it abroad so I'm not too familiar with those voltage ratings.

3. Yes and no. There are a lot of companies like BPT and Goertz that make balance power conditioners. Some people like them, some people hate them. To get a balanced unit like that, which has an isolation transformer in it, will cost you quite a lot of dough and probably won't do as well as one of the ugly jobbies you see on surplus sales.

A Few answers to audio questions

Some Isolation Transformer Info:

The Isolation Transformer simply takes the whole electrical signal from the wall and stores it in a huge iron core on the input side. It then releases it to a smaller iron core on the output side that feeds your components. The key piece is when the electricity is released from the large input iron core to the small output iron core, it cleans the electrical signal according to the pF capacitance, in this case .001 pF is saying that the AC signal is cleaned (or background noise or soundstage) is reduced by 136 db. This is a drastic reduction. THE ONE THING that the Isolation Transformer DOES NOT DO is any kind of Surge Suppression.

The Power Conditioner only works on one leg of the electrical signal. Because it only cleans up one side (either the Hot or Nuetral side), it affects how the Power Conditioner makes the components hooked up to it sound. It's like using a stock power cord or a Dream State power cord or a Shunyata power cord, these affect the sound by the different materials they're made up of. The Power Conditioner USUALLY DOES PROVIDE Surge Suppression.

The bottom line is that the Isolation Transformer cleans the AC without adding any sound of it's own, and it reduces the soundstage noise a lot more than most of the Power Conditioners on the market.

I own an $1800 Transparent PowerIsolator power conditioner, and it doesn't even come close to what the Isolation Transformer did.

The bigger the Kva value, the better because of the AC storage on the input side, the bigger, the better the dynamics and bass power (headroom basically). 1.8 Kva is 1800 watts, 120 watts times 15 Amps. 2.5 Kva is 20 Amps, 3.0 Kva is 25 Amps. They say that the 5 Kva is the 'best' one to have for the headroom and ease, like a 500 horsepower engine will get you to 60 mph faster.

The lower the pF value the better: .005 pF = 126 db noise reduction, .001 pF = 136 db noise reduction and .0005 pF = 146 db noise reduction. Of course when you look at the website, the lower the pF, the more expensive. A 5 Kva with .0005 pF is $2,077.00 plus shipping. I paid $400 for the 2.5kva .001pF unit, though it was used.

More Answers:

1. Yes and no. Your components, like the XPA-1, also generate noise of their own that is sent back along the power lines. That noise infects other components in the chain. That's why many people say they cut the breakers on their refrigerator and microwaves when they are listening to music because it cuts out noise in power lines. By using an Isolation Transformer you are effectively isolating the components from everything else. They are not effected by other components that are plugged in, and they do no effecting themselves.

2. If you look on the surplus sales website, most of the Isolation transformers will tell you voltage in/voltage out. It usually will say 120/120, or 120/220 or 220/120... or any of the other ratings you may fine. Some go as high as 440 volts, others as low as 115. If you need it to work abroad, then look for ones rated 220/220. That means the voltage coming from the wall to the transformer is 220volts and the voltage leaving is 220volts. Often people will use a stepdown transformer from 220-110 to even greater benefit. This helps to prevent the transformer from becoming saturated and going into isolation.

It also means that a 2.4Kva transformer running at 220volts will output about 11amps rather than 20 as it does on a 120volt circuit.

3. Yes. I have used many power cables. I'll be honest, I was VERY skeptical myself at the effects of power cables on a system. But boy was I converted when I brought some home. I have used the upper echelons of Shunyata, Tara Labs, Lessloss, Virtual Dynamics, and a few others. Purist also makes good, but expensive, power cords.

They make the biggest different on CD players or transports. A large gauge power cord makes a good difference on power amps too -- the XPA-1s love a good power cord, the standard cords suck (for lack of a better term).

The basic reasoning is that the power from the wall is what the audio signal is created from. With a CD player, some of that current is used to create the laser that reads the CD, another bit of current is used to create the digital signal, and a third bit of current is used to convert that to an analog signal. If that power coming from the wall is noisy, then the signal you get from the CD player is noisy. This is why power supply design is so important, it helps to filter the noise coming from the wall (among many other things).

A good power cable should also help filter the power coming from the wall by use of capacitance and low resistance (among other things. If you want more info you'd have to call me because it's too much to type up). That being said, I've heard power cables in my system make as big a difference as a component change. They make a bigger difference than speaker cables and interconnects -- depending on the budget you're running anyways.

I am a believer in power conditioning. It makes a huge difference in my system. I'll probably buy another isolation transformer and sell my power conditioner though -- the isolation transformer is more neutral and actually does a better job at cleaning the power. My advice: buy power cables before a power conditioner. A power conditioner will help bring your power cables up another notch.